This invention relates to a two-piece crank hanger set for bicycles wherein crank assembly and bearing preload are accomplished simultaneously and without the use of special tools.
Commercially available bicycle crank hanger sets are typically either one-piece or three-piece.
In one-piece crank hanger sets, both crank arms are integral with a central spindle which is rotatably supported by bearings mounted in the bottom bracket or crank tube.
In three-piece crank hanger sets, a spindle is rotatably supported by bearings mounted in the bottom bracket or crank tube with the crank arms removably mounted on the ends of the spindle.
Although several references have described two-piece crank hanger sets, wherein the spindle is formed integral with the drive side crank arm and the non-drive side crank arm attached to the free end of the spindle, such devices have the bearings mounted in the crank tube in configurations similar to the one and three-piece crank hanger sets. See, for example, U.S. Pat. Nos. 627,597, 3,906,811, and 4,704,919.
In all of these hanger sets, special tools are typically required for assembly and disassembly of the hanger sets and bearings, and the process is somewhat complicated.